Confidence: It's likely to be this, but I can't be certain.
Notes: An 8mm Tachyporinae family rove beetle. Get recommended has just indicated how large a genus this is, if it is indeed a Tachinus beetle. It seemed to bear a resemblence to Tachinus corticinus but there are many and probably others that look like this. It was found on a decaying cow bone dumped over a wall into woodland with other bones. The beetle seemed trapped in the putrid flesh on the bone.